如何成功找到我要上传到Gridfs存储的文件的文件路径

Question

我正在尝试使用gridfs-stream创建一个writestream，然后将其通过管道传输到文件系统中。我无法使用fs.createReadStream将其通过管道传输到文件系统中，因为我没有提供正确的文件路径。我想从表单获取文件路径。错误如下：

我想将正确的文件路径放入fs.createReadStream(INPUT FILE PATH HERE).pipe(writestream)

req.file.path不起作用

req.files.path不起作用

我无法找到正确的req.file.(something)来指定文件路径。

/Users/ronfranz/Projects/Library/node_modules/mongoose/node_modules/mongodb/lib/operations/mongo_client_ops.js:466
      throw err;
      ^

TypeError: Cannot read property 'path' of undefined
    at NativeConnection.<anonymous> (/Users/ronfranz/Projects/Library/library.js:181:25)
    at Object.onceWrapper (events.js:273:13)
    at NativeConnection.emit (events.js:182:13)
    at /Users/ronfranz/Projects/Library/node_modules/mongoose/lib/connection.js:573:13
    at result (/Users/ronfranz/Projects/Library/node_modules/mongoose/node_modules/mongodb/lib/utils.js:414:17)
    at executeCallback (/Users/ronfranz/Projects/Library/node_modules/mongoose/node_modules/mongodb/lib/utils.js:406:9)
    at err (/Users/ronfranz/Projects/Library/node_modules/mongoose/node_modules/mongodb/lib/operations/mongo_client_ops.js:286:5)
    at connectCallback (/Users/ronfranz/Projects/Library/node_modules/mongoose/node_modules/mongodb/lib/operations/mongo_client_ops.js:241:5)
    at process.nextTick (/Users/ronfranz/Projects/Library/node_modules/mongoose/node_modules/mongodb/lib/operations/mongo_client_ops.js:463:7)
    at process._tickCallback (internal/process/next_tick.js:61:11)
[nodemon] app crashed - waiting for file changes before starting...

var express = require('express');
var exphbs = require('express-handlebars');
var session = require('express-session');
var mongo = require('mongodb');
var mongoose = require('mongoose');
var multer = require('multer');
var Grid = require('gridfs-stream');
Grid.mongo = mongoose.mongo
var storage = require('multer-gridfs-storage')({
    url: 'mongodb://localhost:27017/YourDB'
});
var upload = multer({ storage: storage });
/* FOR USE W/ MULTER-GRID-FS STORAGE - CURRENTLY USING GRIDFS-STREAM
var storage = require('multer-gridfs-storage')({
db: connection
file: (req, file) => {
    return {
        bucketName: 'Books',
        filename: 'file_' + Date.now()
    };
}
});
var upload = multer({ storage: storage });
*/
var bodyParser = require('body-parser');
var bcrypt = require('bcrypt');
var app = express();
const fs = require('fs');

// set up handlebars view engine
app.engine('handlebars', exphbs({defaultLayout: 'main'}));
app.set('view engine', 'handlebars');
var port = process.env.port || 8080;
app.listen(port);
app.use(express.static(__dirname + '/public'));

// Setting up cookie parser
app.use(session({
    secret: 'i am the greatest secret of the modern world',
    resave: true,
    saveUninitialized: false
}));

//Uploading files
app.post('/uploadFile/:title', upload.single('file'), function(req, res){
    var conn = mongoose.createConnection("mongodb://localhost:27017/YourDB");
//Making sure the db instance is open before passing into 'Grid'
    conn.once('open', function(){
        var gfs = Grid(conn.db);
        console.log(req.files.path);
    // Creating write steam to stream data to GridFs
        var writestream = gfs.createWriteStream({
        _id: req.file.id,
        filename: req.file.filename,
        mode: 'w',
    });
    fs.createReadStream(req.files.path).pipe(writestream);
    writestream.on('close', function(file){
        console.log('succesfully uploaded to the database!');
    });
      res.render('bookshelf');
    });
});

这是下面的表格

<form id="uploadLinker" action="/uploadFile/The_Lord_of_the_Rings" method="POST" enctype="multipart/form-data">
  <input type="file" name="file" id="fileToUpload">
  <input type="submit" value="Upload" name="submit">
</form>